Accelerated Mass Transfer During Osmotic Dehydration of High Intensity Electrical Field Pulse Pretreated Carrots

Abstract

High intensity electrical field pulse (0.22 to 1.60 kV/cm) pretreatment was tested to accelerate the osmotic dehydration of carrot. Applied energy in the range of 0.04 to 2.25 kJ/kg, increased cell disintegration index in the range of 0.09 to 0.84 with < 1 °C rise in the product temperature. The effective diffusion coefficients of water and solute, determined using a Fickian diffusion model, increased exponentially with electric field strength according to D = A exp(-B/E). The rise in effective diffusion coefficient may be attributed to an increase in cell wall permeability, facilitating transport of water and solute. Such increase was evidenced by cell disintegration index and softening of product.

Recent advances in drying and dehydration of fruits and vegetables: a review

“…PEF treatment-induced cell damage, resulted in tissue softening, which in turn resulted in a loss of turgor pressure, leading to a reduction in compressive strength. The increase in permeability of potato (Azura et al 1996) and carrot (Rastogi et al 1999) tissues by PEF treatment resulted in improved mass transfer during OD. The effective diffusion coeffi cients of water and solute increased exponentially with electric fi eld strength.…”

“…The rate of mass transfer during OD is generally low. Techniques to improve mass transfer are partial vacuum (Rastogi and Raghava Rao 2004), ultra high hydrostatic pressure (Rastogi and Niranjan 2008), high intensity electrical fi eld pulses (Rastogi et al 1999), super critical CO 2 treatment (Tedjo et al 2002) and prior to OD processing and using centrifugal force (Azura et al 1996).…”

Ultrasound-assisted osmotic dehydration and convective drying of apples: Process kinetics and quality issues

“…Due to its low permeability the barrier to the osmotic solution, both water and substances dissolving in vacuolar sap increases (Kucner et al, 2013). Because of the slowness in solid-liquid mass transfer, several methods have been considered to accelerate the kinetics of this process (Cárcel, et al, 2007;Rastogi et al, 2002), among others the application of pulsed vacuum (Escriche et al, 2000), centrifugal forces (Azuara et al, 1996), electrical fields (Ade-Omowaye et al, 2003;Rastogi et al, 1999) or high intensity ultrasound (Cárcel, et al, 2007;Kowalski and Szadzińska, 2014;Mulet et al, 2003;Siucińska and Konopacka, 2014).…”

Effect of non-thermal hurdles in extending shelf life of cut apples

“…However, some other studies have focused on PEF application in combination with other processing methods such as freezing, osmotic dehydration, etc. (Shayanfar et al 2012;Ade-Omowaye et al 2003;Qin et al 1996;Rastogi et al 1999). The moderate field strength applied (1.5 kV/cm) in this study aimed at increasing permeability and not extraction for which higher amounts of energy are required.…”

“…It was proved that the greater the membrane permeability is the faster osmotic dehydration happens (Zhiming and Le Maguer 1997). Therefore, partial damaging of cell membrane can be beneficial in acceleration of mass transfer, which was already proved to be successful by application of PEF (Shayanfar et al 2012;Ade-Omowaye et al 2003;Rastogi et al 1999). This fact was also observed in group B in which PEF was applied for both blanching and pasteurization (Table 1).…”